In the field of carton based packaging for liquid food products, there are generally two main types of systems; roll fed systems and blanks fed systems. An example of roll fed systems is Tetra Brik™ marketed by Tetra Pak, and an example of blanks fed systems is Tetra Recart™ or Tetra Rex™, both marketed by Tetra Pak.
In the roll fed systems, a roll of packaging material is fed to the system. The roll is shaped into a tube, which in turn is filled with a liquid food product. By successively making transversal sealings in the lower part of the tube and cutting of the lower part of the tube packages can be formed.
In the carton blanks fed systems, the packaging material is prepared before being fed to the system by cutting this into pieces, wherein each piece corresponds to one package, and by providing a longitudinal sealing such that each piece is shaped into a sleeve-shaped body. In order to facilitate folding, weakening lines may be provided in the packaging material. The sleeve shaped packaging material pieces are usually referred to as blanks.
In the filling machine these are placed in a magazine, usually in an upright position such that the openings are placed vertically. According to one way of operating a blanks fed system, a blank is fetched from the magazine, erected and placed in a cassette providing for that blank is kept in a position such that a sleeve with a rectangular cross section is formed. Thereafter, one end of the sleeve is closed and sealed such that a package with an open end is formed. Next, the package is filled with a liquid product via the open end, and finally the open end of the package is sealed and closed.
Usually the blanks are produced at one site, sometimes referred to as a converting factory, and transported to another site where the filling system is placed. During the transportation there is a risk that the blanks are squeezed together such that inner sides of the blanks stick to each other and that close lying blanks stick to each other. Therefore, faced with this reality, it is a challenge to make sure that the blanks can be fetched from the magazine at high speeds, i.e. fetching more than one blank per second, and in a robust way, i.e. causing few unwanted interruptions.